1. Field of the Invention
The invention pertains to casting a pipe seal in the wall of a concrete vessel for use in low pressure installations as for example, septic field distribution boxes and septic tanks. More specifically to an apparatus that mounts on a closure in one wall of the mold for molding a wall of the vessel and holds the seal between the walls of the wall mold.
2. Description of the Prior Art
U.S. Pat. No. 5,286,040 patented Feb. 15, 1994, by N. Gavin, describes designs for casting a pipe seal in the concrete wall of a septic tank. A hinged door on one wall of a concrete wall mold contains a closed cup shaped protrusion. A frustoconical plastic seal fits continuously over the closed bottom and frustoconical side wall of the cup and turns backward in a cylinder that extends from the larger diameter end of the frustoconical portion of the seal past the smaller end of the frustoconical portion of the seal.
When the door is closed, the cup positions the free end of the cylinder against the opposite wall of the concrete wall mold. When the concrete hardens, the door is opened, drawing the cup out of the concrete wall, leaving a conical opening in the concrete wall from the larger end of the cup leading to the open larger diameter end of the frustoconical seal.
The cylinder portion of the seal then lines the rest of the opening in the wall which is sealed by the frustoconical portion of the seal. Integrally molded portions of the seal comprising radially extending arms 31 ending in hollow cylindrical bosses that extend parallel to the axis of the seal (FIGS. 2–4) and annular radially extending flange 26 ending in axially extending rim 28 provide mounting points on the concrete wall and a cast-in anchor. U.S. Pat. No. 5,286,040, patented Feb. 15, 1994, is hereby incorporated by reference.
Additional designs for casting low pressure pipe seals in the concrete wall of a septic tank are described in U.S. Pat. No. 4,951,914, patented Aug. 28, 1990, by Meyers et at., U.S. Pat. No. 5,624,123, patented Apr. 29, 1997, by Meyers, and U.S. Pat. No. 5,941,535, patented Aug. 24, 1999, by Richard.